Electromagnetic sounding apparatus with two exciting windings



- fiwi. 29, $25.

HAHNEMANN ELECTROMAGNETIC SOUNDING APPARATUS WITH TWO EXCITING WINDIfiGS Filed April 8, 1921 3 Sheets-Shea; 1

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W. HAHNEMANN ELECTROMAGNETIC SOUNDING APPARATUS WITH TWO EXCITING WINDINGS Filed April 8, 1921 5 Sheets-Sheei 2 WW f I &

pt. 29, W25.

W. HAHNEMANN ELECTROMAGNETIC SOUNDING APPARATUS WITH TWO EXCITING WINDINGS Filed April 8, 1921 3 Sheets-Sheet 5 Patented Sept. 29,1925.

UNITED STATES HAHNEMANN, OF KITZEBEBG,

1,555,366 PATENT ore-Ice NEAR KIEL, GERMANY, ASSIGNOB TO THE FIRM SIGNAL GESELLSGHAFT M. B. H., O]? KIEL, GERMANY. I

mmcrnouaenn'rxcsounnme .arrana'rus WITH TWO nxcrrme wmnmes.

' Application filed April 8, 1921. Serial No. 459,929.

To all whom it'may concern: 7

Be it known that I, WALTER HAHNEL'IANN, citizen of the German Republic, and residing at Kitzeberg,-near Kiel, county of Schleswig-Holstein, State of Prussia, Germany, have invented certain new and useful Improvements in Electromagnetic Sounding Apparatus with Two Exciting Windings, of which the following is a specification.

In the operation of electromagnetic transmitting apparatus for sound waves operated by meansof alternating currents, as a rule, a direct current is employed for the production of a magnetic field (polarization). This auxiliary excitation can indeed be dispensed with and the sounding apparatus be operated unpolarized if it' only has to serve as a transmitter. If, however, it also has to be used as a receiver at the same time the polarization must be maintained for the reception in any case. So long as a direct current source of any desired suitable voltage can be selected for this polarization no difliculties arise. If, however, it is necessary to employ an existing source of potential, for example the existin main voltage in ships installations. for su marine sounding the potential of which, as a rule, is two high, then the polarization windin must be provided 30 with a lar enumber turns in order to avoid the insertion of resistances usi'nglnp energy. ,In conse uence of this, such a voltage is induce in these windings that it is'scarcely possible to insulate the conductors to these windings'in a secure manner.

tromagnetic sounding apparatus provided withtwo windings which are operated without polarization currents during transmitting and aim at the object of avoiding an induced-current in the windings when are not used' during transmittin The invention consistsin the feature t at one of the two windings is sub-divided and itsiparts' are connected in opposition. The arrangement can be so devised that the connectlon ofthe parts of the winding is fixed before hand or that the parts or groups of the indi'ng-are furnis ed with separate leads hich are connected vwitha switching device hich allows them tobe connected at will either in the same direction or in opposition.

the one winding in opposition the efi'ect is J5 produced. that urmg transmlssion no alto;

" The invention is concerned with an elec- By means of the connection of the parts of' currents or at least only a greatly dinatin hed alternating current is induced in minis the winding which is not used during transmission. 1

The invention is diagrammatically illus trated in a'few examples in thedrawing, which shows in Fig. 1, a sounding apparatus with three-core magnets and with the subdivided winding plermanentlv connected in opposition before and; in Fig. 2 an apparatus of the same kind in which the parts of the win ding are separatelyld outand are capable of being connected as. desired."

Fig. 3 shows a sounding apparatus witha four-core magnet and permanently connect- Fig. 3 shows aed parts of the windin specific modification of Fig. 3. Figs. 4 and 5 show a sounding apparatus assembled from four magnet systems likewise with the parts of the wmding permanently connected.

The sounding apparatus is formed by means of a diaphragm 1 in Fig. 1 which car- I ries the armature 2 of an electro-magnet 3.

The diaphragm is fixed to the annular flange 4 of a dome 5 which covers this dome after the fashion of a lid. The middle of the three magnet cores carries a coil b. The two outer cores each carry a coil (1. which latter are connected in series so that their fluxes neutralize one another in the core. When thus connected either the coil 1; or the coils a, as desired, may be energized by the alternating current for transmission. Since, however, the coil b serves for receiving the polarizing current and therefore has a large number of turns preferably the coils a are used for transmitting. They are connected to the alternating current source to b means of the leads (1,, (1 to the switch a. he coil 6 is joined to the direct current mains n, 1:. through the conductors 1),, b, and the chokin coils d 11,. In frontof the choking coils d d, the conductors are bridged by a condenser 7a,. The group 70,, d,, d, serves-for neutralizing the commutator current ripples of the machine supp] ing the mains. v

The telephone t is 'connecte to a late con denser/l1- at 6,, b and in one o the conductors to the mains in this case in b there is connected in front of k, a choking coil for choking back the receiver alternating .cur-

rent.

In the-example of Fig.2, both parts of the winding a are provided with divided tapings a a, and 0,, a, and are so connected to a switching device 8 by means of b, that in the transmitting position as shown in the figure, the parts a of the winding are connected in opposition and the conductor 6 is interrupted. In the receiving position 6 is connected so that the winding b is supplied with currents from the mains while the parts of the windings a are connected in series in the same direction. The telephone is in this case connected to the coil a through a transformer r.

The four core magnet of Fig. 3 possesses four parts a of the winding and a second winding similarly sub-divided into the parts I). The coils are so wound that the flux of each of the pairs of coils a belongin to a coil 1) assist with reference to the coil arranged upon it as is shown in Fig. 3. In this case as in Figure 1 the group of coils (2 serves for transmitting and the oup of coils b at the same time for polarwing and receiving. Naturally also in this case a system of connection can be emp llpyed corresponding to that in Fig. 2.

e telephohe is connected to the respective magnet windings through a transformer r. This transformer connection is also necessary in the case of a large number of turns in the respective coils 1f telephones of a very high resistance are employed. In one of the conductors Z Z leading to the mains a choking coil (1 is a sin inserted. The condenser in the con uctor a, serves for electrically tuning the transmitting circuit.

Figs. 4 and 5 show diagrammatically in an axial longitudinal section and in a section through the line 12, p, of Fig. 4, a magnet system sub-divided into four parts, the parts of which are arranged concentrically about a system consisting of a stem 6 and a tube 7 and which serves as an elastic connecting link. The armature and field magnets of the magnet system are carried by the plates 8 and 9. The stem is fixed at 8 and the tube at 9 and the armature and field magnets oscillate with respect to one another upon exciting the s stem so that the stem and the tube are su jected to extension and compression in longitudinal direction. The conducting leads to the coils are visible in a particularly simplified form in Fig. 5. Whilst the coils b extend throu h all four parts of the magnet, the secon coil consists of four portions a of a winding arranged on each part of the field magnet and Wound alternately in opposite directions throu hout the series.

The coils can The connected in the operating connection according to Fig. 1 er 2; in the latter case each of the two opposite coils of a pair must be connected in series and must be as aratel led out to a switching device simi ar to that iliustrated in Fig. 2. The number of coils can be increased awarding to the greater er smaller number of sub-divisions of the magnet. If the magnet field is divided into an odd number of parts one of the parts of the winding can again be sub-divlded in a corresponding manner into oppositely "connected parts or in case of nee one of the coils can be switched out.

In the examples shown in the fi res the following three cases are especialfy" of interest.

If the sub-divided winding a is only led out of the apparatus at its end points so that its parts cannot be connected up at will then it can only serve as a transmitting coil because durmg unpolarized transmission the polarity of the magnet cores opposite the armature of the magnet is immaterial. It has therefore the 'lower number of turns adapted for the alternating current voltage. The coil 6 during reception conducts the direct current as well as the induced alternating current and has a lar number of turns suited to the high meet current voltage.

If the two op sitely connected groups of coils a are lecf hut of the apparatus y means of separate conductors so .that they are capable of being connected at w1ll in the same directions and in zip osite directions, then two cases arise. f 'the subdivided winding a. is to be used for transmission it has the lower number of turns and during transmission its parts are connected in opposition in order to produce nofield for the other winding. During recep- 100 tion its parts are connected in the same direction and the alternating current is taken from it while the winding b having a higher number of turns is connected to the hi h voltage direct current source.

f the wmdin b which is not sub-divided is to be used or transmission it has the lower number of turns. The groups of the sub-divided windings must be connected in opposition during transmission, during re- 110 ception the groups of the sub-divided windings are connected in the same direction and are connected to the high voltage source of direct current while the receiving alternating current is taken from the winding which 115 is not sub-divided.

The bringing into prominence of the three cases illustrated does not exclude the possibility of other methods of connection acoordmg to the invention. Also it is not 120 necessary that the sub-division of the one coil must be externally rceptible but rather this efiect can be pro need by suitably arrang the windings of both ln'nds in the same ding space. Finally also no com- 1% plate unifoity in the fields of the parts of the winding connected in opposition is necessary but rather it is suficient if the remaining induction due to the connection in op otitres in so far reduced that the insulatlon 1% of the leadin out conductors presents no particular di culty.

The connections of thecoils and the otherin a switchboard sothat all switching connections can be affected as far as possible with a single movement of a switch.

I claim 1. In an electromagnetic sound signalling apparatus for sending and receiving sounds, the combination of an exciting coil, a polarizing coil and an electromagnet core system common to both coils, an armature for said core system and a diaphragm operatively connected with said armature, one of said coils being sub-divided into several portions, a switching device and electrical connections between said device and said coils and the subdivisions thereof for connecting the coil subdivisions in series with or opposite to each other, to increase or neutralize respectively their electromagnetic efi'ect.

2. In a sound rsignalling apparatus, an electromagnet, and two exciting coils both having said magnet in common with each other, an armature for said electromagnet and a diaphragm operatively connected with said armature, one of said coilsbeing adapted to polarize the said electromagnet and the other of said coils being divided into a pluralityof groups of turns ada ted to roduce opposmg magnetic fluxes, t e divi ed coilhavmg a. small number of turns and being adapted to operate as a transmitting coil and the polarizing coil having a large number of windings and being adapted to operate as a receiving coil, and a switching device for suitably connecting said divided groups of coils, to produce the desired direction of the magnetic fluxes.

3. In a sound signalling equipment, an apparatus comprising an electromagnet and two exciting coils, both having said magnet in common with each other, an armature for said electromagnet and a diaphragm opera tively connected with said armature, one of said coils being undivided and having a large number of turns and the other coil having tectin a small number of turns, divided into a plurality of groups and being adapted to operate as a transmitting 0011, leads from the groups of turns and from the undivided coil extending out of the apparatus, a source of alternating current, a source of continuous current, a detecting device, and a switching device connected to the said leads and adapted to connect the said groups of turns of the divided coil in opposition and to the source of alternating current to produce op posing fluxes in said coils when the apparatus is used for sending, and also adapted to connect the said groups to the detecting device so as to produce cooperatingfluxes, said device being also adapted to connect the said undivided coil to the source of continuous current when the apparatus is used for receiving.

4. In a sound signalling equipment, an apparatus comprising an electromagnet core system, two exciting coils having said sys tem in common'with each other, an armature for said electromagnet and a diaphragm operatively connected with said armature, one of said coils bein undivided and having a large number 0 turns and the other coil having a small number of turns divided into a plurality of grou s' all placed in the same winding space an on the same core portion of said electromagnet system and being adapted to operate as a transmitting coil, leads from the groups of turns and from the undivided coil extending out of the apparatus, a source of alternating current, a source of continuous current, a dedevice, and a switching device connecte to said leads and adapted to connect said groups of turns of the divided coil to the source of alternating current so as to produce opposing fluxes when the apparatus 1s used for sending, and also adapted to connect the said groups to the detecting device so as to produce cooperating fluxes,

and to connect said undivided coil to the source of continuous current when the apparatus is used for receiving.

In testimony whereof I afiix my signature.

WALTER HAHN'EMANN. 

